Yacas for EPOC

YACAS (Yet Another Computer Algebra System) is an easy to use, general purpose Computer Algebra System, a program for symbolic manipulation of mathematical expressions. It uses its own programming language designed for symbolic as well as arbitrary-precision numerical computations. The system has a library of scripts that implement many of the symbolic algebra operations; new algorithms can be easily added to the library. YACAS comes with extensive documentation (320+ pages) covering the scripting language, the functionality that is already implemented in the system, and the algorithms we used. The entire free source code (including the documentation) can also be found in the source code distribution.

YACAS consists of approximately 22000 lines of C++ code and 13000 lines of scripting code, with 170 functions defined in the C++ kernel and 600 functions defined in the scripting language.

The main advantages of YACAS are: free (GPL) software; a flexible and easy-to-use programming language with a comfortable and adjustable syntax; cross-platform portability (Unix, Windows, Macs, EPOC32, etc.) and small resource requirements; and extensibility.

Yacas for EPOC Machines

Read the original "EpocYacas.txt" file, written by Ayal Pinkus, the main author of Yacas. Then read the generic "Readme.txt" text and the more specific "ReadmeEpoc.txt" (almost a copy of this web page). It is important to install the "Stdlib.SIS" before "YacasEpoc.SIS".

The most complete distribution of Yacas runs on Linux, the EPOC version currently lacks some features, mainly concerning input and output :

"copy & paste" are partially implemented by the user interface so that they only work inside Yacas, but the user can export any result as text files, for example : ToFile("C:\TaylorSin.txt") PrettyForm(Taylor(x,0,9) Sin(x)). You can replace "PrettyForm" by "Echo" to avoid long outputs
the RC file is fixed at "C:\System\Apps\Yacas\YacasRC.txt" and has its commands read every time Yacas is started
the history file is stored as "C:\System\Apps\Yacas\YacasHistory.txt"
"?function", "Help", "quit", "restart", "Ctrl+C" (stop the currently running calculation), command-line options, etc., are not implemented. To read the documentation use "?" or "??" on EPOC, or browse the HTML, TXT of PDF files outside the Yacas session
graphical output ("Plot2D" and "Plot3DS") is not implemented

A Yacas 1.0.56 session can be seen below on a real Psion Revo+; if you want to see more example sessions running on EPOC32, go to the Screenshots Gallery.

For details about Yacas releases, read the "Changes.html" and "ChangesYacasEPOC.txt" documents. As Yacas has been developed from 1999, the releases have steadily implemented more code (in C++ and in the form of Yacas scripts), so it is continuously being larger in RAM usage.

The table below, as well the above "changes" documents, may help you decide which version is better for you or you EPOC32 machine. If you have plenty of available RAM, just use the last version.

Version of Yacas	1.0.43	1.0.53rev2	1.0.56*
Release date	18/11/2000	14/11/2002	15/11/2003
Minimum RAM (1)	0.6 MB	1.4 MB	1.9 MB
Normal use of RAM (2)	1.0 MB	2.6 MB	3.6 MB
Maximum RAM (3)	1.5-2 MB	3.7 MB	4.4 MB
Installation size	386 KB	1.09 MB	1.37 MB

the minimum of RAM is measured when started
the normal use of RAM was obtained after calculating "50!", "N(1/243,70)", "D(x) Tan(x)^2" and "Integrate(x) x*Sin(x)^2", so the loaded scripts are assumed to represent a typical Yacas session with respect to script loading. After automatically loading the scripts, each input/output is faster (see the Screenshots Gallery) and takes memory only to stored results in variables
the maximum of RAM happens when many scripts are loaded or variables are stored
versions 1.0.53rev2 and 1.0.56 include 366 KB of help files

(*) Obs.: Yacas 1.0.56 without the plugins "PCRE" and "FileScanner", with little changes from 1.0.55, so Yacas 1.0.55 for EPOC is not available for download. Also, Yacas 1.0.54 is not available here as the used memory ranges between releases 1.0.53rev2 and 1.0.56.

So even a Psion Revo with 8 MB can run Yacas if there are not a lot of applications installed. In this case, trying to read Yacas HTML docs will take a lot of memory using Web or Opera for EPOC, so the TXT docs are more recommended.

Yacas 1.0.43

Yacas 1.0.5x solves almost all the above limitations about the/and is faster than the release 1.0.43 for EPOC, but :

the installation process is somewhat slow because the "scripts" directory has approx. 200 files, but it is better than using the compressed "scripts.dat" file which takes up to 0.5 MB of RAM
output is limited to 5KB characters, more than this will close Yacas, due to the client/server implementation

There are also many improvements on the client&server user interface, version 1.40, when compared to Yacas 1.0.43 for EPOC :

"copy & paste" now work but just inside Yacas, the selection can use "Shift" + "Left", "Right", "Ctrl+Left" and "Ctrl+Right"
new cursor navigation keys: "Fn+Left", "Fn+Right", "Ctrl+Left" and "Ctrl+Right"
"Shift+Del" keypress work as a delete key
the scroll bars are turned on by default and their vertical and horizontal history size are increased
"Up" and "Down" keypresses also show the current line and the total lines of the history in a message window
trailing backslash "\" at end of each continued line makes possible the use of commands spanning multiple input lines using up to 1 KB
messages "Starting Yacas..." and "Running..." are shown when starting Yacas and when a calculation is running
line numbers are shown in input and output heads, i.e., "In(n)>" and "Out(n)>"
the calculation time in seconds is displayed between "In(n)>" and "Out(n)>"
"Esc" aborts the history navigation
removed extra empty line after error message, between print output and "Out(n)>" and in the end of outputs using 'PrettyPrinter ("PrettyForm")'
the command "FindFile" works
the command "ToFile" is able to create output text files if they do not exist
the menu interface is redesigned to follow Epoc look&feel (NEW)
EPOC help is available on the menu "Tools", or "?" opens the reference function list and "??" opens the "Getting Started with Yacas" text (NEW)
"Edit/Complete line Ctrl+L" (or Tab) matches the results from the line history file and shows them on a dialog listbox (NEW)
"Edit/Complete command Ctrl+M" (or Ctrl+Tab) matches the results from more than 800 symbols and shows them on a dialog listbox (NEW)
the "Commands" menu pane packs hundreds of Yacas commands and symbols in categories, the selection yielding the command templates (NEW)
fixed a bug on "FromBase", "ToBase" and "Fast..." functions, where they were incorrectly returning 0 if Yacas 1.0.54/55/56 v1.30 was used (NEW)

Read "ChangesYacasEPOC.txt" for more details.

Future of Yacas for EPOC/Symbian (wish list)

There are many possible improvements regarding Yacas on EPOC machines :

extend "copy & paste" to export & import to the EPOC32 clipboard and other features on the client for EPOC
add more command templates to the "Commands" menu pane
implement "SystemCall", etc., on the server for EPOC
fix the limitation of maximum characters of the outputs
try to optimize the memory used by the server and the scripts
create a Yacas OPX so that an OPL program could talk to the Yacas server, sending inputs and receiving outputs
based on this Yacas OPX, I would like to create an open source frontend written in OPL more suitable for Symbian smartphones where the current C++ client could not be (easy) ported

About Symbian machines, due to memory constraints (4.4 MB of operating RAM) to run Yacas 1.0.56, the Nokia 92xx Communicator and/or some Series 60 (Nokia 7650/ 3650, Siemens SX1, etc.) could run only an older Yacas release, like 1.0.53rev2. But the UIQ machines (SonyEricsson P800/900, Motorola A920, etc) have 7-8 MB of operating RAM, and the newer Series 80 and Series 90 machines (to be release in 2004) are expected to have more RAM available, so it would be nice to :

build a Symbian OS 6.0 and 6.1 version of Yacas to run on Nokia 92xx Communicators and Series 60 machines, even if it is an older release like 1.0.53rev2, so it would be a preparation to release Yacas 1.0.56 for new machines running Series 60 (with large max. heap RAM), 80 (Nokia 9500) and 90 (Nokia 7700)
build an UIQ release of Yacas 1.0.56

The above lists are expected to attract attention of C++ programmers interested to contribute in developing Yacas on EPOC/Symbian devices.

Resuming my thoughts, as the EPOC and Symbian machines approaches the power of Windows/Linux/Mac notebooks (of some years ago), a Yacas release targeted to EPOC/Symbian would be ideal because Yacas is memory efficient and an open source project, contrary to many other Computer Algebra Systems (CAS), and Symbian is the best OS for smartphones IMHO. I support the future vision that PDA & smartphones running CAS will be used as educational tools by millions of students and as common calculation tools by many other professionals around the world.

Yacas 1.0.56 for EPOC & Console Client v1.40 (550 KB zip file) (22/03/2004)
Yacas 1.0.53rev2 for EPOC & Console Client v1.40 (473 KB zip file) (22/03/2004)
Yacas 1.0.43 for EPOC (192 KB zip file)
"Yacas user's function reference" in EPOC Help format (88 KB zip file) courtesy of Rolf Jebasinski (22/03/2004)
"Getting Started with Yacas" in EPOC Word format with outlines (19 KB zip file) courtesy of Rolf Jebasinski (22/03/2004)
Yacas documentation in ASCII text format (132 KB zip file, 01/2003) more suitable for constrained memory EPOC machines
Yacas on-line documentation or in HTML format and PDF format files
Yacas 1.0.56 source code (2.14 MB zip file), read the "epoc/HowToCompile.txt" (to be updated)

for Epoc

(Psion 5/5mx, Revo,7/netBook, etc.)